| 摘要 |
PURPOSE:To form an optical wave guide of a small propagation loss by alternately laminating >=2 kinds of II-VI compd. semiconductors on a substrate, then protecting only the optical wave guide part with a mask and diffusing the impurities into the superlatice exclusive of the mask. CONSTITUTION:After ZnS 2 is grown as a lower clad layer on a GaAs (100) substrate 1 by a crystal growth method, ZnS 3 and ZnS 4 are alternately grown and laminated as the optical wave guide layer consisting of the superlattice 5. Patterns are drawn on the growth layer by photolithography using a photoresist 6 as a mask for ion implantation and the resist of the parts exclusive of the optical wave guide part is removed and impurity ions are implanted 7 over the entire surface of the substrate. The crystallinity is restored in the implanted layer exclusive of the mask part by a subsequent heat treatment and the impurities are simultaneously diffused in the crystal and, therefore, the superlattice structure is broken to form mixed crystals 9. On the other hand, the optical wave guide 8 of the superlattice is formed in the mask part. The three-dimensional confinement of light is attained by a difference in refractive index between both. The waveguide of the low loss is formed in this way. |
